Routine diagnosis of respiratory virus infections caused by type A and B influenza, parainfluenza, respiratory synctial, and adenoviruses has been encumbered by relatively slow tissue culture methodology. Detection and identification of viral antigen directly in clinical specimens, without prior cultivation in cell culture, would provide a means of rapid viral diagnosis. Methods capable of this are electron microscopy, immunofluorescent (IF) (or immunoperoxidase (IP)) staining of cells from the site of infection, radioimmunoassay, and enzyme immunoassay (EIA). For reasons of safety, simplicity, and versatility we are focusing on EIA methods. An EIA with B-D-galactosidase as the label and the fluorometric substrate 4-methylumbelliferyl-B-D-galactoside for detection of enzyme activity will be developed. Influenza A/USSR will be used as a model system with a projected sensitivity level of less than 30 TCID 50. Once achieved and adapted to an indirect EIA (antispecies globulin labeled), comparable assays for influenza B/HK, respiratory syncytial virus, parainfluenza virus types 1, 2, and 3, and the adenovirus group will be developed. Preliminary testing will involve tissue culture pools of virus. Final testing with clinical specimens will compare the EIA method with IF (or IP) staining of cells and standard tissue culture methods. The eventual goal of this research is to develop diagnositic methods that will supply physicians with etiologic information rapidly enough to influence patient care.